The present disclosure relates generally to circuit breakers and particularly to a contact arm assembly for a circuit breaker.
Multipole circuit breakers configured to protect multiphase electrical circuits are known in the electrical circuit protection industry. The variety of constructions of multipole circuit breakers include blow open and non-blow open contact arms, overcentering and non-overcentering contact arms, single contact pair arrangements with the contact pair at one end of a contact arm and a pivot at the other end thereof, double contact pair arrangements (referred to as rotary breakers) with a contact pair at each end of a contact arm and a contact arm pivot intermediate (typically centrally located between) the two ends, single housing constructions with the circuit breaker components housed within a single case and cover, and cassette type constructions (referred to as cassette breakers) with the current carrying components of each phase housed within a phase cassette and each phase cassette housed within a case and cover that also houses the operating mechanism. Multipole circuit breakers are generally available in two, three, and four pole arrangements, with the two and three pole arrangements being used in two and three phase circuits, respectively. Four pole arrangements are typically employed on three phase circuits having switching neutrals, where the fourth pole operates to open and close the neutral circuit in a coordinated arrangement with the opening and closing of the primary circuit phases. While existing circuit breakers are considered suitable for their intended purpose, the art of circuit breakers may be improved by providing a rotary contact arrangement having compression springs arranged between a rotor assembly and a rotary contact arm that maintain good electrical connection between the contacts during quiescent operating conditions, enhance contact separation upon occurrence of overcurrent conditions, and provide for ease of assembly.